A coagulase secreted in semen and synthsised in the prostate. PLEASE NOTE: TEST CAN ONLY BE ADDED TO A SAMPLE WITHIN 8 HOURS OF COLLECTION

Indication

Investigation for prostatic carcinoma. PSA can also be used in the clinical staging of the disease and follow-up.

Additional Info

PSA is not considered suitable for screening the general population for disease but men over 50 are able to request the test after discussion with their GP.
PSA measurement should be followed up by a DRE. PSA increases with clinical disease stage: PSA >50 ug/L is indicative of metastatic disease with >100 ug/L suggesting bony metastases. PSA is also useful for monitoring treatment of prostatic carcinoma. It is useful to measure PSA post prostatectomy with elevated concentrations being indicative of residual disease. It is also useful for predicting tumour recurrence months before any clinical signs. False negative PSA results are seen in 9% cancer patients.
The minimum repeat interval for PSA is one month.
PSA can be increased following DRE, UTI etc. For more information see: http://www.pathology.leedsth.nhs.uk/pathology/Portals/0/PDFs/BP-2013-05.pdf.

Concurrent Tests

na

Dietary Requirements

na

Interpretation

If PSA is >3 ug/L in patients less than 70 years of age presenting to primary care with symptoms suggestive of prostate cancer they should be referred for urological opinion. Note false negative results can also be obtained.